Study On Water Quality Evaluation Of Baihua Lake And Its Spatial And Temporal Changes

Water resources were the foundation on which living things depend,and they were also one of the elements that constitute ecosystems and living bodies.However,with the rapid increase in the number of people on the planet and the high-speed operation of the economy,the impact of humans on the surface environment had gradually deepened.The problems of waste of water resources,excessive consumption and pollution had caused the quality of the water environment to decline year by year,especially a large number of untreated labor.The pollution caused by the direct discharge of agricultural wastewater and domestic sewage into rivers,lakes,rivers,and seas was more prominent.As one of the components of the hydrological system,lakes had an irreplaceable role in human activities and social and economic development,especially in urban areas.Lakes were more closely related to humans.At present,in order to meet the needs of production and life,lakes had been seriously polluted.To this end,many scholars at home and abroad had explored lake water quality assessment,and strived to put forward effective comprehensive prevention and control measures for lake pollution control.This move can also continue to deepen the understanding of changes in lake water environment and is important for the protection of lake water quality.Practical significance.In this paper,the Baihua Lake Reservoir in Guiyang City was taken as the research object,and the physical and chemical parameters of Baihua Lake water body from 2012 to 2017 were statistically and regularly determined.The NH⁺_4-N,TN,TP,pH,DO,T,COD,COD_Mn,SD and Chl.a was the main parameter for evaluation,using single factor evaluation method,grey correlation analysis method,fuzzy comprehensive evaluation method,Nemero index method,comprehensive nutrition status index evaluation method to evaluate the water quality of Baihua Lake and analyze the temporal and spatial trends of water quality of Baihua Lake,The law of changes in water quality over the years.The research results of this paper were as follows:1.The water quality of Baihua Lake calculated by the single factor analysis method was light pollution-cleaner,and the main pollutants were TN,TP and COD.According to the Nemero index method,the lake as a whole was of Class?and?water quality,and Class?water quality appears at No.5 sampling point.The main pollution indicators of the lake are TN,TP and NH4+-N.The single factor and Nemero method evaluated The water quality of Baihua Lake was poor,but from the overall trend of water quality changes over the years,it could be seen that the water quality of Baihua Lake was improving year by year,and the water quality results were more in line with the actual water quality of Baihua Lake;the calculation results of fuzzy comprehensive evaluation method and gray correlation analysis method show that Baihua Lake as a whole It was the water quality of Class I and V.The main pollution parameters were TN,TP,DO and COD,and the membership values of Class IV and V were relatively large.Overall,the main pollution parameters of the lake were showing a declining trend year by year,and the water quality was improving year by year.Among all types of land use in Baihua Lake,construction land and cultivated land had a"source"effect on TN,TP and NH3-N,while forest land had a"sink"effect on TP and TN.2.According to the comprehensive nutritional status index method,Baihua Lake's TSI???value changes from 2012 to 2016 with a stable average value of 32.91,which is a mesotrophic state,and the TSI???value generally shows a downward trend year by year.The average value of TSI???at the upper sampling point of the lake is higher than that of the other sampling points,which is related to the enrichment of nutrients carried by the water body in the upstream of Baihua Lake.The overall change was a gradual increase trend from the front of the dam to the tail of the reservoir.The nitrogen-phosphorus ratio was between24.750¹13.010 mg×L-1,which was a reservoir controlled by high nitrogen and phosphorus.3.Water quality control suggestions for Baihua Lake:?1?The lake has high nitrogen and phosphorus,and can plant floating leaves and floating plants that absorb nitrogen and phosphorus.These two types of aquatic plants did not require lake water depth.Sediment dredging,closure of sediment,and clearing of flushing and other measures for remediation;?2?Construction land and cultivated land have a“source”effect on Baihua Lake TN,TP,NH3-N.The treatment of pollutants should start from the regular monitoring of the lake's main tributaries and the discharge of Hongfeng Lake.The generated"three wastes"must be discharged after reaching the standard and develop into a green ecological industry.